1. Field of the Invention
The present invention relates to a backlight module and a light guide plate thereof, and more particularly to a light guide plate with microstructures and a backlight module including the same.
2. Description of the Related Art
FIG. 1 shows a schematic view and FIG. 2 shows a bottom view of FIG. 1, of a conventional backlight module disclosed in Taiwan (R.O.C.) patent publication no. 200504424. The backlight module 1 includes a plurality of LEDs 11 and a light guide plate 12. The LEDs 11 are used to provide a plurality of light beams. The light guide plate 12 is used to receive the light beams from the LEDs 11. The light guide plate 12 has a first surface 121, a second surface 122, a side surface 123, a plurality of grooves 124 and a plurality of dots 125. The first surface 121 is opposite the second surface 122, and the side surface 123 is adjacent to the first surface 121 and the second surface 122. The grooves 124 are formed by cutting or injection molding and are disposed on the side surface 123. The grooves 124 are empty space and have openings on the side surface 123. The grooves 124 are intervally spaced so as to reduce hot spots in front of the LEDs 11. The groove 124 is triangular and has two edges 1241 and an intersecting point 1242. The edges 1241 intersect at the intersecting point 1242.
The LEDs 11 face the side surface 123 and are disposed in the grooves 124, so that the light beams enter the light guide plate 12 through the grooves 124, and the light beams are then transmitted to a diffusion film (not shown) through the second surface 122. The dots 125 are printed on the first surface 121 of the light guide plate 12 to form a pattern, so as to reflect or refract most light beams back to the interior of the light guide plate 12.
The backlight module 1 has the following disadvantages. The light beams from the LEDs 11 must pass through the air in the grooves 124 before entering the light guide plate 12. Because of the inclination of the edges 1241, a hot spot will still occur at the intersecting point 1242. Additionally, the dots 125 are not distributed over the entire area of the first surface 121. That is, there is a large blank margin 1211 between the leftmost dot 125 and the side surface 123. The blank margin 1211 has no dot; therefore, large area of the blank margin 1211 will lower the luminance of the light guide plate 12. Additionally, part of the energy of the light beams form the LEDs 11 will lose because of the large gap between the LEDs 11 and light guide plate 12.
Therefore, it is necessary to provide a backlight module and a light guide plate thereof to solve the above problems.